The excessive overflow of tears down a cheek due to an obstruction in the nasolacrimal drainage system is a relatively common problem. The excessive overflow, referred to as epiphora or "watering eye", is often accompanied by infection with attendant inflammatory reaction.
Normally, tears are drained from the eye through the nasolacrimal drainage system (hereinafter the lacrimal system) which includes an upper and lower canaliculus, each of which communicates with its respective eyelid through an opening known as the punctum. The other ends of the canaliculi join together the common canaliculus which then enters the lacrimal sac. The tears then drain through the lacrimal sac into the upper end of the nasolacrimal duct. The lower end of the nasolacrimal duct opens into the nose.
Presently, minor obstructions of the lacrimal system commonly are treated by dilatation using metal probes in children. In adults obstructions of the nasolacrimal duct are treated by performing a dacryocystorhinostomy (DCR), during which the lacrimal sac is surgically connected with the nasal cavity. DCR is a relatively major surgical procedure involving making an incision next to the bridge of the nose near the lacrimal sac, breaking through the bone to access the nose, and cutting away a portion of the lacrimal sac. The newly created opening into the nose is referred to as the ostium. In children who do not respond to probing or placement of silicone tubes in the lacrimal system a DCR is performed.
As many as one in ten DCR operations fail due to subsequent closure of the ostium. The ostium can be reopened surgically, but few patients wish to undergo the trauma of a second surgery which involves the excising of additional tissue, anesthesia, and subsequent packing of the nose with absorbent material for two to three days following the surgery.
A number of techniques presently are attempted to avoid the trauma of a second surgery. Dilatation of the ostium with a metal probe, intranasal dilatation with a muscle hook, and dilatation with a knotted suture are used with varying degrees of success. A silicone tube frequently is attached to the probe so that the silicone tubing is installed in the lacrimal system to serve as a stent in an attempt to maintain patency of the ostium. However, the canaliculus is typically only 0.5-1.0 mm in diameter and the internal diameter of the stent is therefore relatively small and ineffective. These techniques usually do not succeed in reopening the ostium for a sufficient period of time. Often, the tissue surrounding the ostium simply recloses after the probe is removed, even when the silicone tubing stent is present.
One such stent is a silicone catheter with an inflatable balloon which is positioned within the patient's lacrimal sac. The catheter maintains communication between the lacrimal sac and the nose. The balloon is of a sufficient size to prevent postoperative migration of the catheter to the nasal fossa. After the patient is healed, the balloon is deflated and the catheter is removed by pulling it through the patient's nostril. In other words, the balloon is not used for dilatation, but simply serves as a retaining element for the stent.
Obstruction of a canaliculus can also occur. Various solid, rigid instruments have been used to dilate a canalicular stenosis. Commonly, a rigid metal probe is used followed by silicone intubation as a stent. However, the number of failures is high and an operation called a conjunctivodacryocystorhinostomy (CDCR) must frequently be performed. The CDCR involves bypassing the lacrimal system by surgically creating an opening from the eye into the nose. A short pyrex tube is then installed so that it creates a passage from the eye straight into the nose. This procedure is poorly tolerated by most patients. Further, the CDCR can become obstructed, particularly if the pyrex tube becomes dislodged.
Additionally, obstruction of the punctum is very common. Again, the punctal stenosis is usually treated with a solid metal probe with varying degrees of success.
A novel method of treating lacrimal obstructions is described in Becker et al., "Balloon Catheter Dilatation in Lacrimal Surgery", Opthalmic Surgery 20:193-198 (March, 1989). The article describes balloon dilatation of four patients with failed DCR. A standard Bowman probe was inserted through the canaliculus and lacrimal sac and advanced through the nasal ostium into the nose. The metal probe was removed, and a 0.014 inch diameter guide wire was advanced along the same path. The distal end of the guide wire was grasped by a hemostat in the nose and pulled outwardly from the nose. A USCI Profile Plus 4.0 mm coronary balloon catheter, having a deflated profile of 0.042 inch and a balloon length of 20 mm, was guided over the wire. An ink mark previously placed on the catheter shaft proximal to the proximal end of the full-diameter region (center region) of the balloon was aligned with the punctum. The balloon was located in the lacrimal sac and extended through the ostium into the nose, and the ink mark was aligned with the punctum. Two dilatations were performed at 10 bar inflation pressure. The guide wire and balloon then were withdrawn.
The technique disclosed by Becker et al. is useful, but involves a number of time consuming steps including the insertion of a guide wire through the lacrimal system, and then separately advancing the balloon catheter over the guide wire. It would be desirable to utilize fewer steps in treating obstructions within the lacrimal system, and to use a procedure which is similar to the use of opthalmic probes with which opthamologists are familiar.
In a separate subject area, balloon catheter dilatation has been used to treat stenotic blood vessels, urinary tract obstructions, and strictures of the gastrointestinal tract. In percutaneous transluminal coronary angioplasty, for example, a guide wire is maneuvered along a selected coronary artery until an occlusion is reached. A balloon catheter is then advanced over the guide wire by pushing on the proximal end of the balloon catheter. After the balloon is positioned within the occlusion, it is inflated to dilatate the occlusion. Frequently, the first balloon catheter is withdrawn and a second, larger-diameter balloon catheter is positioned to perform a subsequent dilatation. No suggestion has been made, other than the Becker et al. 1989 article, to use balloon catheters in the treatment of an obstructed lacrimal system by performing dilatation of the obstruction.